/*
* Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
*
* iPhone port by Simon Oliver - http://www.simonoliver.com - http://www.handcircus.com
*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/

#include "GLES-Render.h"
#include "cocos2d.h"
#include <stdio.h>
#include <stdarg.h>
#include <string.h>

#ifndef WIN32
#include <alloca.h>
#endif

USING_NS_CC;

float currentscale = 1;	// amount of pixels that corresponds to one world unit, needed to use glPointSize correctly

GLESDebugDraw::GLESDebugDraw()
: mRatio(1.0f)
, mPointSizeLocation(-1)
, mColorLocation(-1)

{
	this->initShader();
}

GLESDebugDraw::GLESDebugDraw(float32 ratio)
: mRatio(ratio)
, mPointSizeLocation(-1)
, mColorLocation(-1)
{
	this->initShader();
}

void GLESDebugDraw::initShader(void)
{
	mShaderProgram = ShaderCache::getInstance()->getGLProgram(GLProgram::SHADER_NAME_POSITION_U_COLOR);
	mPointSizeLocation = mShaderProgram->getUniformLocation("u_pointSize");
	mColorLocation = mShaderProgram->getUniformLocation("u_color");

	//_tex = Director::getInstance()->getTextureCache()->addImage("HelloWorld.png");
}

void GLESDebugDraw::DrawPolygon(const b2Vec2* old_vertices, int vertexCount, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	b2Vec2* vertices = (b2Vec2*)alloca(sizeof(b2Vec2)* vertexCount);
	for (int i = 0; i<vertexCount; i++)
	{
		vertices[i] = old_vertices[i];
		vertices[i] *= mRatio;
	}

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, vertices);

	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r, color.g, color.b, 1);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1, vertexCount);


	CHECK_GL_ERROR_DEBUG();
}

void GLESDebugDraw::DrawFlatPolygon(const b2Vec2* old_vertices, int32 vertexCount, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	b2Vec2* vertices = (b2Vec2*)alloca(sizeof(b2Vec2)* vertexCount);
	for (int i = 0; i<vertexCount; i++) {
		vertices[i] = old_vertices[i];
		vertices[i] *= mRatio;
	}

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, vertices);
	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r, color.g, color.b, 1);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);


	glDrawArrays(GL_TRIANGLE_FAN, 0, vertexCount);
	CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1, vertexCount);
}


void GLESDebugDraw::DrawSolidPolygon(const b2Vec2* old_vertices, int vertexCount, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	b2Vec2* vertices = (b2Vec2*)alloca(sizeof(b2Vec2)* vertexCount);
	for (int i = 0; i<vertexCount; i++) {
		vertices[i] = old_vertices[i];
		vertices[i] *= mRatio;
	}

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, vertices);
	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r*0.5f, color.g*0.5f, color.b*0.5f, 0.5f);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r*0.5f, color.g*0.5f, color.b*0.5f, 0.5f);

	glDrawArrays(GL_TRIANGLE_FAN, 0, vertexCount);

	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r, color.g, color.b, 1);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(2, vertexCount * 2);

	CHECK_GL_ERROR_DEBUG();
}

void GLESDebugDraw::DrawCircle(const b2Vec2& center, float32 radius, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	const float32 k_segments = 16.0f;
	int vertexCount = 16;
	const float32 k_increment = 2.0f * b2_pi / k_segments;
	float32 theta = 0.0f;

	GLfloat* glVertices = (GLfloat*)alloca(sizeof(GLfloat)* vertexCount * 2);
	for (int i = 0; i < k_segments; ++i)
	{
		b2Vec2 v = center + radius * b2Vec2(cosf(theta), sinf(theta));
		glVertices[i * 2] = v.x * mRatio;
		glVertices[i * 2 + 1] = v.y * mRatio;
		theta += k_increment;
	}

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);
	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r, color.g, color.b, 1);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1, vertexCount);

	CHECK_GL_ERROR_DEBUG();
}

void GLESDebugDraw::DrawSolidCircle(const b2Vec2& center, float32 radius, const b2Vec2& axis, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	const float32 k_segments = 16.0f;
	int vertexCount = 16;
	const float32 k_increment = 2.0f * b2_pi / k_segments;
	float32 theta = 0.0f;

	GLfloat* glVertices = (GLfloat*)alloca(sizeof(GLfloat)* vertexCount * 2);
	for (int i = 0; i < k_segments; ++i)
	{
		b2Vec2 v = center + radius * b2Vec2(cosf(theta), sinf(theta));
		glVertices[i * 2] = v.x * mRatio;
		glVertices[i * 2 + 1] = v.y * mRatio;
		theta += k_increment;
	}

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);
	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r*0.5f, color.g*0.5f, color.b*0.5f, 0.5f);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r*0.5f, color.g*0.5f, color.b*0.5f, 0.5f);

	glDrawArrays(GL_TRIANGLE_FAN, 0, vertexCount);

	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r, color.g, color.b, 1);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	// Draw the axis line
	DrawSegment(center, center + radius*axis, color);

	CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(2, vertexCount * 2);

	CHECK_GL_ERROR_DEBUG();
}

void GLESDebugDraw::DrawSegment(const b2Vec2& p1, const b2Vec2& p2, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	GLfloat    glVertices[] =
	{
		p1.x * mRatio, p1.y * mRatio,
		p2.x * mRatio, p2.y * mRatio
	};
	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);
	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r, color.g, color.b, 1);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	glDrawArrays(GL_LINES, 0, 2);

	CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1, 2);

	CHECK_GL_ERROR_DEBUG();
}

float smoothstep(float x) { return x * x * (3 - 2 * x); }

void GLESDebugDraw::DrawParticles(const b2Vec2 *centers_old, float32 radius, const b2ParticleColor *colors, int32 count)
{

	// normally this is how we'd enable them on desktop OpenGL,
	// but for some reason this is not applying textures, so we use alpha instead
	/*glEnable(GL_POINT_SPRITE);
	glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE);*/

	const float particle_size_multiplier = 8;  // no falloff
	const float global_alpha = 0.35f;  // instead of texture

	mShaderProgram->setUniformLocationWith1f(mPointSizeLocation, radius * mRatio * particle_size_multiplier);

	GL::blendFunc(GL_SRC_ALPHA, GL_ONE);

	b2Vec2 *centers = (b2Vec2 *)alloca(sizeof(b2Vec2)* count);
	for (int i = 0; i<count; i++) {
		centers[i].x = centers_old[i].x *mRatio;
		centers[i].y = centers_old[i].y *mRatio;
	}

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, centers);
	glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_TEX_COORDS, 0, 0, 1, 1);

	if (colors)
	{
		// hack to render with proper alpha on desktop for Testbed
		//b2ParticleColor * mcolors = const_cast<b2ParticleColor *>(colors);
		/*for (int i = 0; i < count; i++)
		{
		mcolors[i].a = static_cast<uint8>(global_alpha * 255);
		}*/
		//glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, 0, &colors);

		mShaderProgram->setUniformLocationWith4f(mColorLocation, colors[0].r, colors[0].g, colors[0].b, global_alpha);
	}
	else
	{
		glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, 1, 1, 1, global_alpha);
		mShaderProgram->setUniformLocationWith4f(mColorLocation, 0.1, 0.2, 0.3, global_alpha);
	}

	//glBindTexture(GL_TEXTURE_2D, _tex->getName());
	glDrawArrays(GL_POINTS, 0, count);
	CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1, count);
}


void GLESDebugDraw::DrawTransform(const b2Transform& xf)
{
	b2Vec2 p1 = xf.p, p2;
	const float32 k_axisScale = 0.4f;
	p2 = p1 + k_axisScale * xf.q.GetXAxis();
	DrawSegment(p1, p2, b2Color(1, 0, 0));

	p2 = p1 + k_axisScale * xf.q.GetYAxis();
	DrawSegment(p1, p2, b2Color(0, 1, 0));
}

void GLESDebugDraw::DrawPoint(const b2Vec2& p, float32 size, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	GLfloat                glVertices[] = {
		p.x * mRatio, p.y * mRatio
	};

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);
	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r, color.g, color.b, 1);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	//    mShaderProgram->setUniformLocationWith1f(mPointSizeLocation, s_pointSize);

	glDrawArrays(GL_POINTS, 0, 1);


	CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1, 1);

	CHECK_GL_ERROR_DEBUG();
}

void GLESDebugDraw::DrawString(int x, int y, const char *string, ...)
{
	//    NSLog(@"DrawString: unsupported: %s", string);
	//printf(string);
	/* Unsupported as yet. Could replace with bitmap font renderer at a later date */
}

void GLESDebugDraw::DrawAABB(b2AABB* aabb, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	GLfloat                glVertices[] = {
		aabb->lowerBound.x * mRatio, aabb->lowerBound.y * mRatio,
		aabb->upperBound.x * mRatio, aabb->lowerBound.y * mRatio,
		aabb->upperBound.x * mRatio, aabb->upperBound.y * mRatio,
		aabb->lowerBound.x * mRatio, aabb->upperBound.y * mRatio
	};

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);
	//    glVertexAttrib4f(GLProgram::VERTEX_ATTRIB_COLOR, color.r, color.g, color.b, 1);
	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	glDrawArrays(GL_LINE_LOOP, 0, 4);

	CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1, 4);

	CHECK_GL_ERROR_DEBUG();
}
